1. Dropsonde RICO Atmospheric Technology Division/ NCAR Terry Hock
NCAR GPS Dropsonde Overview

2. NCAR Dropsonde History
NCAR developed the first dropsonde in the early 1970’s
Added Omega Wind Finding mid 1970’s (ODW)
Developed L2D2 (Lightweight LORAN Digital Dropsonde) in 1984
Developed LOD2 (Light weight Omega Digital Dropsonde) 1986
Developed GPS Dropsonde 1996 for DLR, NOAA, NCAR.
Dropsonde Technology Licensed to Vaisala as RD-92

3. Overview of Dropsonde Measures (PTH)
Pressure
Temperature
Humidity (2-sensors)
Wind speed and direction (GPS receiver)
Sensor sample rate 2Hz (both PTH and GPS)
Size: 2.75” Dia., 16” length
Mass: 390 grams

4. Dropsonde Components Codeless GPS receiver PTH Vaisala module
400 MHz telemetry transmitter
HC11 8-bit Microprocessor
Lithium battery pack
Sondes are manufactured by Vaisala inc, in Louisville, CO
(licensed through UCAR)

5. Temperature Humidity QC

6. Temperature Humidity QC & raw

7. Wind Data QC

8. Wind Data QC and raw

9. Dropsonde Fall Velocity

10. ER-2 Temperature Profile

11. ER-2 Humidity Profile

12. ER-2 Temperature & Humidity Profile

13. DLR Falcon U & V GPS Winds

14. Sonde Fall Time Typical Fall Times 10,000 ft. – 4.5 Minutes

15. Aircraft Data System 4- Channel Telemetry Chassis Computer System
400 MHz Receivers
GPS Proccessing Card
PTH Buffer
Sonde Interface
Computer System
AVAPS Drop Software
ASPEN Software (Post Processing QC, Temp Drop, Skew-T)

16. Aircraft Data System
4 channel system allows for up to 4 sondes in the air simultaneously
Channel can be re-used typical within 4 minutes of previous drop
System requires one operator, if rapid drops are required two operators may be necessary

17. RICO Dropsonde Overview
280 Dropsondes
NCAR C-130 Aircraft
Standard 4 channel system
~ 12 Dropsonde released per flight
Dropsondes released over water east of Barbuda

18. RICO Dropsonde Staffing
One ATD Operator in the field (Korn)
Dropsonde Operator for aircraft flights
Sonde inventory
Preliminary QC of the data
Data archival
Interface with the P.I.’s
Equipment maintenance
One operator can release dropsonde at a rate of one sonde every ~ 5 minutes, if drops ar required more frequent than a student assistant is required.

19. Technical Issues Dropsonde GPS Receiver (Winds)
Aircraft P-Static (in high E-Fields)
Manufacturing Reliability
RF Multi-path